Flocking apparatus



June 13, 1944. e. s. HIERS FLOCKING APPARATUS Filed April 2, 1941 'Tss FIGJI F'IGHI INVENTOR GLEN SEF'TON HlERS $1 A ORNEY Patented June 13, 1944 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to an improved apparatus for flocking adhesively coated base fabrics of cotton or other materials such as paper, cardboard, pressed board, felted material and the like.

More particularly, these improvements are directed to the production of textile flocked fabrics the flock portion of which is composed of fibers preferably of pile forming length which are fixed at one of their ends to a base fabric of cotton or other material by an adhesive. The flock may be short textile fibers of wool, mohair, cellulose acetate, casein fibers, silk, viscose, or blends of any or all of these fibers.

It has long been known that the beating or vibrating as by a motor driven polygonal bar of an adhesively coated base fabric willcause cut flock to form a pile face with an end of the pile forming flock embedded in the adhesive. The British patent to Cartolux No. 393,017 is merely illustrative of this general prior practice. Fabrics produced by beating alone are however somewhat deficient in pile face density and pile erectness.

It is further known to employ high voltage electrostatic forces in the flocking of adhesively coated base fabrics, but high voltage forces appear incapable of adequately driving the fibers into the adhesive, with the result that pile fabrics so produced while having density of face coverage and erectness of pile have been characterized by unsatisfactory durability and wearing qualities. In addition, pile fabrics so produced may have an excessive pile face density which results in stiff- -ness or boardiness and hence lack of draping qualities desirable for some purposes.

Mechanical beater processes provide a superior anchorage of the flock fibers than high voltage electrostatic methods and are, of course, desirable for this reason. The investment in equipment and maintenance of beater mechanism is substantially less than for electrostatic devices involving high potential forces.

Cotton base fabrics are highly desirable as backings for flocked fabrics because of their strength, flexibility and availability. These cotton base fabrics or fabrics substantially of cotton will when beaten on the back or rapidly vibrated in known ways produce the pile face of deficient pile erectness and density above referred to. Such results can be obtained with a rapidly rotating motor driven steel bar in the known way.

I have found that a rapidly rotating steel bar beating the back of a cotton fabric of normal atmospheric moisture content will not create an electrostatic charge measurable on a gold leaf electroscope. If, however, an electrostatic field is created independently of the cotton base fabric by the means of frictional engagement of the beater bars and other means or solely by independent frictional means, pile forming flock particles can be caused to mutually repel each other and stand substantially upright in the adhesive. It will be understood that wool fibers, being curved or crescent shaped, will not be caused to take on a straight upright position, but these fibers are distributed and oriented to the extent permitted by their shape. These improvements are especially important in connection with the application of wool flock to a cotton base fabric, because the mutual repulsion set up by electrostatic field will overcome to. an important degree the tendency of curved wool flock to form small masses of flock. This tendency to form masses is peculiar to wool which is serrated and curved and hence has felting properties.

I have discovered b frictionally engaging two or more materials at least one and preferably both or all of which are of superior dielectric material to the cotton or like coated base material that an electrostatic field may be created of sufficient intensity to efiect distribution and orientation of flock textile fibers, so that if an adhesively coated base fabric be placed and vibrated within the field as by beating the back thereof, a flocked pile fabric may be produced having not only good anchorage of fiber to adhesive but also excellent distribution, erectness and density of pile.

The means employed to vibrate the fabric may desirably but not necessarily perform a double function by being one of the means whose frictional engagement with another or other materials produces the electrostatic field. For example, in a preferred embodiment of my invention I interpose between the beater and the cotton or like base fabric an apron of wool, silk or other superior dielectric material, so that the beater performs the double function of vibrating the base fabric and generating the electrostatic field. By using a beater having a surface of good dielectric property such as of hard rubber, Lucite, Bakelite, Cellophane and the like, the intensity of the field may be increased.

The dielectric apron, in addition to being interposed between the beater and base fabric, may if desired be positioned to also contact the beater on the opposite side from that of the cotton base fabric. Or the apron may engage the beater only on the under or opposite side, that is, the beater may be placed between the dielectric apron and the cotton base fabric. And by drying the dielectric apron and/or cotton base fabric to bone dryness the intensity of the electrostatic field may be further intensified.

It is apparent from the above that modifications and variations are intended to be included within my concept but in the broadest aspect I contemplate the use of a frictionally produced electrostatic field of measurable intensity to control the distribution and positioning of pile flock particles being applied to a coated cotton or like base and the use of a vibratory force to drive the particles into the adhesive of the adhesively coated cotton base material.

An object of my invention is to provide a low potential electrostatic charge independently of the base fabric which will orient textile pile flock fibers being applied to a cotton or like base material.

Another object is to insure uniformity of result by regulating the moisture content of the base fabric to a predetermined range of moisture content, which range is below the normal atmospheric moisture content.

Another object is to reduce the moisture content of cotton base fabrics to below normal and thereafter creating a low potential electrostatic charge by frictional means which will orient pile forming textile flock particles in a flocking operation.

Another object is to produce by frictional engagement a low potential electrostatic field which is used to distribute and orient flock fibers being deposited upon an adhesively coated cotton base fabric.

These and other objects of invention will be manifest from a consideration of the following description, claim and drawing, in which:

Figure I is a diagrammatic side elevational view of apparatus employing my invention.

Figure II is a modification showing the belt entirely out of contact with the base fabric but in contact with the rapidly rotating beater bars.

FigureIII is a modification showing the means for creating the field entirely out of contact with the base material or beaters.

Referring to the drawing, in Figure I there is illustrated a base fabric ID of cotton or like material fed from supply roll ll, passed between tension adjusting rolls l2 and I3 and over guide roll I4 into drying chamber l5 where the normal moisture content of the fabric may be reduced or removed. The drying chamber may be of any convenient type, and wire covered card clothing roll l6 for feeding the fabric along may conveniently be located within the drying chamber.

After emerging from the dryer, the fabric is passed over guide rolls I1, I 8, l9 and and between brushes 2l and 22, which brush into troughs 23 and 24 any lint, dirt or other foreign matter that may have become deposited on the fabric.

An adhesive 25 of rubber cement, pyroxylin or other suitable compositions may be applied as by doctor blade 23, roller 2T being used to support the fabric at the point ofapplication.

The adhesively coated fabric is then passed beneath hopper 28 having screen bottom 29 and containing fiock fibers 30-which are pushed by rotating blade 3| through the screen and caused to drop upon the coated fabric positioned or passing continuously beneath. It is to be understood that the terms adhesive and adhesively coated as used above and in the claim refer to the coating prior to drying or other solidification.

' The fabric is then passed under tension over one or more polygonal bars which are rapidly rotated by conventional means such as an electrical motor (not shown) and which beat the fabric and cause it to rapidly vibrate. In the 11- lustration, Figure I, a series of three bars 32, 33 and 34 is depicted, but it will be understood that this number is merely illustrative and that any reasonable number, including a single bar, may be used. The bars may be of steel or other metal, but are preferably surfaced with a material of good dielectric property such as hard rubber, Lucite, Bakelite, or Cellophane. Bars 32 and 34 are shown as covered and bar 33 is steel.

A flexible apron 35 of wool, silk or other material having dlelectric properties superior to the cotton base fabric and which may be supported as by rolls 36, 31, 38 and 39, is interposed between all the polygonal bars and the base fabric. Rolls 40 and 4| are included for supporting a blanket if it is desired to keep it out of contact with the base fabric.

As depicted in the illustration, the arrangement of the supporting rolls is such that the dielectric apron may be interposed between the base fabric and any one or more of the bars. Or all the bars may beat the base fabric directly and the dielectric apron may be caused to contact only the lower sides of the bars. Can driers 42 and 43 may, if desired, be provided to dry the apron to bone dryness.

The first polygonal bar or bars is or are preferably rotated in the direction in which the base fabric is moving, while the last bar or bars may be rotated in the opposite direction. All the bars may, however, be moved in the same direction of rotation if desired.

In order to compensate for the fact that the heaters tend to throw the fibers slightly in the direction of their respective rotation, the fabric may preferably be moved over the heaters at a slight incline. For example, the heaters may desirably be arranged in'crown formation, that is, with the center heater or beaters occupying a higher position than the forward and rearward ones, the

forward and center beaters rotating in the direction of fabric movement and the rearward beaters rotating against the movement of the fabric. This arrangement is of course merely illustrative of an arrangement I have found satisfactory and is not intended to be limiting in any way.

During the beating operation the electrostatic field generated by the frictional engagement between the rapidly rotating bars and the dielectric apron causes the deposited fibers, through mutual repulsion to distribute and orient themselves in substantially erect position and t e vibratory or beating action forces them into the adhesive where they become firmly secured. It will be understood that wool fibers, being curved or crescent shaped, will not be caused to take on a straight upright position, but these fibers are distributed and oriented to the extent permitted by their shape.

After leaving the heaters, the fabric may be passed over guide roll 44 to beater 45 where the excess or unsecured fibers are beaten off to collecting-tray 46. The fabric is then taken over guide rolls 41, 48, 49 and 50 to steam chamber 52, where the adhesive is vulcanized or set, after which the fabric is taken over guide rolls 5| and 53 to the final roll-up 54. If desired, finishing steps, such as shearing and brushing, may be incorporated into the process after the adhesive is vulcanized or hardened.

The electrostatic field may be created by means independent of the base and/or of the heaters. In the first case (Figure II), I position a hopper 80 having screen 6| through which flock 62 may be sifted by the aid of agitator 63. Beater bars 64, 65 and 66, covered with Lucite strips, contact the base fabric and a wool or silk blanket I5 supported by rollers 61, 68, 69, 10, H and 12 o as to move through can driers I3 and I4. The charge produced is carried to and through the base fabric.

In Figure 111 a different arrangement completely independent of the base fabric is illustrated. The hopper 0. having screen 8|, through which wool pile flock .2 may be sifted by the aid of agitator 83, is positioned between steel beaters 84 and 85 and over a portion of the base fabric where the field is created. Driving rollers 81 and 88 move wool or silk blanket 86 over Lucite or other rollers 89, SI and 9| to create a field among the wool flock which breaks up the a gregates of wool flock.

Drying the base fabric is not essential to mv concept according to the illustrated embodiments but is preferred and insures uniformity in production.

Having described my invention but wishing to be limited only by my claim, I claim:

In an electrostatic field generator for flocking fabrics the combination with means for longitudinally feeding a base fabric and means for applying flock fibers thereto of, means comprising a pair of relatively movable members of dielectric materials in frictional contact when in motion for generating an electrostatic field through which the base fabric moves to orient the flock particles deposited on the base fabric, and means for imparting relative motion to said members, one of said members being a rotatable beater and another of said members being an endless web.

GLEN SEF'ION HIERS. 

